Yesterday I found the first azalea caterpillars of the year. These tiny caterpillars had just hatched from the white eggs you see
Newly hatched azalea caterpillars. Notice white eggs on the leaves in the background. Photo: SD Frank
in the background. You can scout for these bright eggs in August before the caterpillars hatch and remove them. I think these caterpillars are worth having though since they are very beautiful. Actually the caterpillars are prettier than azaleas tend to be this time of year and they will eat all the leaves stippled by lace bugs! You can read more about these caterpillars that feed on azaleas and blueberries in a post from last August.
Maple spider mites (Oligonychus aceris) are common and damaging pests of maple trees throughout the Eastern United States. These spider mites overwinter on the trunk and
Adult maple spider mite. Photo: AG Dale
branches of maple trees and migrate to the underside of leaves in the spring. Once there, they use their mouthparts to pierce leaf cells and feed on cell sap. This causes fine flecking called stippling and eventually leaves turn gray or brown after heavy feeding. Maple spider mites have multiple generations per year which enables them to become quite abundant during a single season. These pests are a more serious problem in nurseries due to the close proximity of potted trees and applications of broad spectrum insecticides like permethrin. For example, our research has shown that applications of permethrin targeting ambrosia beetles can wipe out natural enemies and result in secondary maple spider mite outbreaks. Maple spider mites can also be abundant on landscape trees. Trees in parking lots and along roads are most likely to be infested.
Maple spider mite egg attached to tree bark. Photo: AG Dale
A hand lens or stereo microscope is necessary for correct identification of these mites but damage is a good indicator of infestation. They are dark brown or red with hairs along their backs and have eight legs while some immature forms exhibit green coloration and have six legs. Red eggs of these mites can be found on tree limbs and yellow or clear eggs can be found on leaf surfaces. Treatment for these pests includes foliar applications of acaricides. Maple cultivars differ in susceptibility to maple spider mites and other maple pests like leafhoppers. A chapter in a recent free ibook IPM for Select Deciduous Trees in Southern Nursery Production describes more
Maple spider mite damage. Photo: AG Dale
about management of maple pests and other tree pests. A recent article in Nursery Management and a fact sheet describes mite biology and management. This time of year trees may not be sold until fall so the condition of leaves is not as much of an issue. On landscape trees mite damage reduces fall color and summer color because leaves are gray, yellow, or brown instead of green.